"The storms blew through Hampton Roads on a Thursday in August, and after the storms came runoff, lots of it, shooting off roofs and pavement into storm drains, and a week after the runoff came the red tide.

At Ocean View in Norfolk, the waves were mahogany with pale-red caps, stained by a sudden growth spurt of algae.

“How long have you seen it there?” Chris Moore, a science advocate for the Chesapeake Bay Foundation, asked the lifeguard on duty. “It came up, like, yesterday,” the lifeguard said.